Various approaches are used to reduce contamination in liquids and gases, such as in municipal drinking water supplies, ultrapure water systems for industrial processing and pharmaceutical manufacture, water and reagents for use in experimentation, gases used in sterile rooms, and the like. Such approaches are often used to reduce or eliminate the need for chemical aerosols, chemical preservatives, microfiltration, and like materials as well as processes for the treatment of liquids and/or gases.
An apparatus for irradiating media by means of a UV light that is external to a tubular body has been described, e.g., U.S. Pat. No. 4,948,980, which is herein incorporated by reference. U.S. Pat. No. 4,948,980 provides an apparatus having a tubular body through which medium to be irradiated flows, and at least two UV light sources with reflectors arranged externally in relation to the tubular body and having parallel axes. The apparatus described in U.S. Pat. No. 4,948,980 relies on specular reflectors to control the uniformity of the light pattern delivered by the lamps. The lamp sources are relatively flat and aligned on their edges within the specular reflector in order to minimize the optical effects in the reflector. Unfortunately, U.S. Pat. No. 4,948,980 describes approaches that significantly limit the amount of dosage that can be provided to effectively treat a liquid or gas. For instance, U.S. Pat. No. 4,948,980 does not appreciate the use of a high reflectivity diffuse reflector to treat a liquid or gas with a low absorption cross-section nor does the patent anticipate a large increase in dose delivered to a target as the net reflectivity of the entire chamber approaches 100 percent.
U.S. Patent Application Publication No. 2004/0166018, herein incorporated by reference, describes a UV air sterilization chamber comprising inner surfaces having a diffuse reflective behavior. The sterilization chamber includes an inlet aperture and an outlet aperture for air to flow through the chamber and a light source emitting a UV light. Unfortunately, the approaches described in U.S. Patent Application Publication No. 2004/0166018 suffer from several problems. For example, since these approaches do not attempt to increase the transparent or translucent containment volume compared to total chamber volume, the performance of the apparatus is not maximized. In addition, the reflector used is not isolated from the medium being treated; and no option exists for replacing lamps without opening the chamber, thereby increasing the difficulty in using and maintaining the system.
In U.S. Pat. No. 6,228,332, herein incorporated by reference, discloses a short-duration, high-intensity pulsed broad-spectrum polychromatic light being used to treat water for the deactivation of microorganisms. As described in U.S. Pat. No. 6,228,332, deactivation of microorganisms in water involves illuminating the water with at least one short-duration, high-intensity pulse of broad-spectrum polychromatic light. The system includes a watertight housing having an inlet port and an outlet port for the flow water. A tubular light source for deactivating microorganisms and a tubular baffle for directing the water flow are positioned within the watertight housing. Water enters the inlet port and flows between the watertight housing and the tubular baffle in one direction, around the end of the tubular baffle and back through the center of the tubular baffle in a second direction exiting the outlet port. In this case, water flows around the tubular light source which provides at least one short-duration, high-intensity pulse of broad-spectrum polychromatic light. However, the approaches described in this patent also suffer from several problems. For example, the efficiency of the approaches described in U.S. Pat. No. 6,228,332 are limited, because these approaches do not use a reflective surface or substantially enclose the treatment chamber in order to treat the liquid or gas target.